There were 310 million guns in the U.S. in 2009 (a Congressional Research Service figure I have no reason to dispute), a figure that likely grew to perhaps 350 million by 2013.

These guns result in ~33,000 deaths in 2013, of which 64% were suicides, leaving ~500 accidental deaths and 11,200 due to homicides (these are official CDC figures reported in Table 10)

There were 269 million registered vehicles in the U.S. in 2013.

These result in ~33,000 deaths a year, roughly half of which are drivers (these are official NHTSA statistics).

In this sharply divided country, there surely is also strong disagreement about the extent to which government ought to be protecting citizens from self-harm. But I presume that a broad spectrum of the public on both sides of the aisle would agree there is an appropriate government role in protecting citizens from being harmed by one another. So if we leave aside self-inflicted deaths, the average car is 1.8 times as risky as the average gun. That is, my owning a car is 80 percent more likely to result in the death of another person my owning a gun.